TY - JOUR
T1 - AXL expression on homeostatic resident liver macrophages is reduced in cirrhosis following GAS6 production by hepatic stellate cells
AU - Pop, Oltin-Tiberiu
AU - Geng, Anne
AU - Flint, Emilio
AU - Singanayagam, Arjuna
AU - Ercan, Caner
AU - Possamai, Lucia
AU - Patel, Vishal C
AU - Kuenzler, Patrizia
AU - Meier, Marie-Anne
AU - Soysal, Savas
AU - Hruz, Petr
AU - Kollmar, Otto
AU - Tatham, Kate C
AU - Ward, Josie K
AU - Müllhaupt, Beat
AU - Weber, Achim
AU - Wendon, Julia
AU - Niess, Jan Hendrik
AU - Heim, Markus
AU - Semela, David
AU - Weston, Christopher
AU - Antoniades, Charalambos G
AU - Terracciano, Luigi Maria
AU - Triantafyllou, Evangelos
AU - Brenig, Robert G
AU - Bernsmeier, Christine
N1 - Copyright © 2023 The Authors. Published by Elsevier Inc.
PY - 2023/3/31
Y1 - 2023/3/31
N2 - BACKGROUND & AIMS: AXL and MERTK expression on circulating monocytes modulated immune responses in patients with cirrhosis (CD14
+HLA-DR
+AXL
+) and acute-on-chronic liver failure (CD14
+MERTK
+). AXL expression involved enhanced efferocytosis, sustained phagocytosis, but reduced TNF-α/IL-6 production and T cell activation, suggesting a homeostatic function. Axl was expressed on murine airway in tissues contacting the external environment- but not interstitial lung-, and tissue-resident synovial lining macrophages. We assessed AXL expression on tissue macrophages in patients with cirrhosis.
METHODS: Using multiplexed immunofluorescence we compared AXL expression in liver biopsies in cirrhosis (n=22), chronic liver disease (n=8), non-cirrhotic portal hypertension (n=4) and healthy controls (n=4). Phenotype and function of isolated primary human liver macrophages were characterised by flow cytometry (cirrhosis, n=11; control, n=14) ex vivo. Also, AXL expression was assessed on peritoneal- (n=29) and gut macrophages (n=16) from cirrhotic patients. Regulation of AXL expression was analysed in vitro and ex vivo using primary hepatic stellate cells (HSCs), LX-2 cells and GAS6 in co-culture experiments.RESULTS: AXL was expressed on resident (CD68
+) but not tissue-infiltrating (MAC387
+) liver macrophages, hepatocytes, HSCs, or sinusoidal endothelial cells. Prevalence of hepatic CD68
+AXL
+ cells significantly decreased with cirrhosis progression: (Healthy 90.2%; Child Pugh A 76.1%; B 64.5%; C 18.7%, all p<0.05) and negatively correlated with MELD and CRP (all p<0.05). AXL-expressing hepatic macrophages were CD68
highHLA-DR
highCD16
highCD206
high. AXL expression also decreased on gut and peritoneal macrophages from cirrhotic patients, but increased in regional lymph nodes. GAS6, enriched in the cirrhotic liver, appeared to be secreted by HSCs and down-regulate AXL in vitro.
CONCLUSIONS: Decreased AXL expression on resident liver macrophages in advanced cirrhosis, potentially in response to activated HSCs-secreted GAS6, suggests a role for AXL in the regulation of hepatic immune homeostasis.
AB - BACKGROUND & AIMS: AXL and MERTK expression on circulating monocytes modulated immune responses in patients with cirrhosis (CD14
+HLA-DR
+AXL
+) and acute-on-chronic liver failure (CD14
+MERTK
+). AXL expression involved enhanced efferocytosis, sustained phagocytosis, but reduced TNF-α/IL-6 production and T cell activation, suggesting a homeostatic function. Axl was expressed on murine airway in tissues contacting the external environment- but not interstitial lung-, and tissue-resident synovial lining macrophages. We assessed AXL expression on tissue macrophages in patients with cirrhosis.
METHODS: Using multiplexed immunofluorescence we compared AXL expression in liver biopsies in cirrhosis (n=22), chronic liver disease (n=8), non-cirrhotic portal hypertension (n=4) and healthy controls (n=4). Phenotype and function of isolated primary human liver macrophages were characterised by flow cytometry (cirrhosis, n=11; control, n=14) ex vivo. Also, AXL expression was assessed on peritoneal- (n=29) and gut macrophages (n=16) from cirrhotic patients. Regulation of AXL expression was analysed in vitro and ex vivo using primary hepatic stellate cells (HSCs), LX-2 cells and GAS6 in co-culture experiments.RESULTS: AXL was expressed on resident (CD68
+) but not tissue-infiltrating (MAC387
+) liver macrophages, hepatocytes, HSCs, or sinusoidal endothelial cells. Prevalence of hepatic CD68
+AXL
+ cells significantly decreased with cirrhosis progression: (Healthy 90.2%; Child Pugh A 76.1%; B 64.5%; C 18.7%, all p<0.05) and negatively correlated with MELD and CRP (all p<0.05). AXL-expressing hepatic macrophages were CD68
highHLA-DR
highCD16
highCD206
high. AXL expression also decreased on gut and peritoneal macrophages from cirrhotic patients, but increased in regional lymph nodes. GAS6, enriched in the cirrhotic liver, appeared to be secreted by HSCs and down-regulate AXL in vitro.
CONCLUSIONS: Decreased AXL expression on resident liver macrophages in advanced cirrhosis, potentially in response to activated HSCs-secreted GAS6, suggests a role for AXL in the regulation of hepatic immune homeostasis.
KW - TAM receptors
KW - innate immunity
KW - cirrhosis
KW - resident liver macrophages
U2 - 10.1016/j.jcmgh.2023.03.007
DO - 10.1016/j.jcmgh.2023.03.007
M3 - Article
C2 - 37004869
SN - 2352-345X
JO - Cellular and molecular gastroenterology and hepatology
JF - Cellular and molecular gastroenterology and hepatology
ER -